Character mistake: Almanzo says he hasn't seen his brother Royal in 10 years, but in fact he saw him not long ago as he looked after his 2 sons who were terrors, and at that time Royal didn't even have a daughter.
Visible crew/equipment: When Chester and Cassie are in The Cabin, Chester is looking through the picnic basket while Callie holds on the Indian's hand and talks to him. In the scene behind Callie is an unidentified man who disappears when the scene cuts to Chester. (00:47:00)
Factual error: An egotistical, prissy and dishonest lawyer like Mr. Fletcher wouldn't make the mistake of allowing his name to be misspelled on his office door. It reads "Winfred Fletcher." His first name, as it's pronounced throughout the episode, is "Winford." (00:26:50)
Revealing mistake: Samuel Clemens (Mark Twain) spends a night in North Fork while the wheel of a stagecoach he is riding in is being repaired. Clemens is fishing at a lake and Mark McCain says, "You've caught a fish " Clemens tells the boy to reel in the fish. The boy jerks the rod and pulls the fish out of the water. The fish is obviously a fake which a stagehand had attached to the hook. The fish is motionless and is not even wet.
Continuity mistake: When Audra takes lemonade to Will inside the place where he's working as a forger, the pitcher has a liquid which is the true color of lemonade and there's not much left in the pitcher...less than 1/4 of what it could hold. When she comes out of the building, it has the color of iced tea and there's almost half a pitcher of it, which is way more than there should be.
Character mistake: Trivette hands the man in yellow a bullet recovered from the plane Walker and Alex were traveling on, which was shot down by an assassin flying a P-51 Mustang. This man, and later Trivette, mistakenly refer to the round as a "50mm," when in reality, Mustangs were equipped with M2 Browning .50 Caliber (12.7 mm) machine guns. (00:30:25)
Factual error: We see how the accident-prone Wilton Parmenter was a soldier at Appotomatox during the Civil War when he sneezed. Union soldiers mistook his sneezing for a call to regroup and charge, winning the battle. Wilton Parmenter was awarded the Medal Of Honour. Accident-prone, even in his moment of glory, when the medal was pinned on Wilton's chest it pierced his skin, drawing blood. Wilton was therefore awarded the Purple Heart, becoming "the only soldier in history to get a medal for getting a medal." This was not possible, for the "Purple Heart" (or "Badge Of Military Merit", to use its proper title) awarded to US soldiers wounded in action, was only instituted in 1932. (Before somebody corrects me, George Washington did institute the award for some distinguished combatants during the War Of Independence, but it was never awarded during the nineteenth century, and revived in 1932).
Other mistake: Dr. Mike spots a charred Bible within the charred piles of books, and heads into the church. The Reverend is giving a sermon on morality, and offers Dr. Mike the floor and she briefs about certain stories in the book, which would be considered scandalous, without mentioning the book's title, then hands it to the Reverend who agrees such stories are scandalous, until he turns it over, to see that its 'The Holy Bible'. Being a Reverend, he should know The Bible cover to cover, but reacts surprised or shocked over the mentioning of the scandalous stories. (00:36:00 - 00:41:00)